POS0143 COMPOSITION AND ASSOCIATIONS OF THE GUT MICROBIOTAWITH PERIPHERAL LYMPHOCYTE SUBSETS AND CYTOKINES IN IDIOPATHIC INFLAMMATORY MYOPATHIES
Authors: Q. Y. Su, J. Q. Zhang, J. Luo, J. Qiao, S. X. Zhang, X. Li, C. Wang
Journal: Annals of the Rheumatic Diseases (2022)

Background The idiopathic inflammatory myopathies (IIM) are a group of acquired myopathies characterized by inflammatory lymphocytes infiltrates in muscle tissue 1 .Gut microbiota serves as a critical environmental component of autoimmune disease pathogenesis such as IIM 2 . Objectives This study sought to investigate the composition of gut microbiota and the relationship between microbiota structure and lymphocyte subpopulations and cytokines in IIM patients to recommend feasible intervention strategies. Methods Faecal samples were taken from 37 IIM patients and 37 age- and gender- matched healthy controls (HCs) in a sterile environment placed into the Second Hospital of Shanxi Medical University. Microbiome profiling was performed by sequencing of the V3-V4 variable regions of the 16S rRNA gene and the peripheral T lymphocyte subsets of these participants were assessed by flow cytometry. The clinical laboratory data such as erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) and immunoglobulin were also determined. In terms of gut microbia, the diversity and richness was evaluated from two aspects: alpha diversity and beta diversity with the indices of ACE, Chao1, Shannon and Simpson. Analyses were conducted using R version 4.0.1. Pearson correlation was applied to assess the relationship between the relative abundances of bacterial genera and clinical parameters, and p &lt; 0.05 was considered to be statistically significant. Results The α-diversity analysis of the richness (Chao1) and diversity (Shannon and Simpson) were reduced in IIM samples compared with those of HCs (Figure 1A, p &lt; 0.05). Bray curtis distance-based beta diversity analysis revealed significant differences in the microbial community between IIM and HCs (Figure 1B, p = 0.001, ANOSIM). Detailly, at the genera level, IIM patients had a higher abundance of Enterococcus, Veillonella, Streptococcus, et al. and a lower abundance of Roseburia, Lachnospira, Klebsiella, et al(Figure 1D, p &lt; 0.05). In IIM patients, Fusobacteriota correlated positively with the ratio of Th1 cells (Figure 1E, p &lt; 0.01), and there was a significant positive correlation between Synergistota and B lymphocyte (Figure 1E, p &lt; 0.01). Besides, Euryarchaeota and Cyanobacteria were both positively and significantly related to IL-6, IFN-γ and C-reactive protein (CRP) (Figure 1E, p &lt; 0.001). Conclusion Richness and diversity of intestinal flora in IIM patients were impaired, which might participate in the pathogenesis of IIM by disturbing lymphocyte subpopulations and cytokines. Regulating intestinal flora and restoring homeostasis might become a critical therapeutic methods of IIM. References [1]Xu Y, Sun J, Wan K, et al. Multiparametric cardiovascular magnetic resonance characteristics and dynamic changes in myocardial and skeletal muscles in idiopathic inflammatory cardiomyopathy. J Cardiovasc Magn Reson 2020;22(1):22. doi: 10.1186/s12968-020-00616-0. [2]Mariampillai K, Granger B, Amelin D, et al. Development of a New Classification System for Idiopathic Inflammatory Myopathies Based on Clinical Manifestations and Myositis-Specific Autoantibodies. JAMA Neurol 2018;75(12):1528-1537. doi: 10.1001/jamaneurol.2018.2598. Acknowledgements This work was supported by the National Natural Science Foundation of China (No. 82001740). Disclosure of Interests None declared